内置高温体倾斜多孔腔体中自然对流的LBM模拟

摘要

To investigate the flow and heat transfer mechanism of fluid in an inclined porous cavity with an inlaid hot square obstacle,Lattice Boltzmann method was adopted to investigate the phenomenon of natural convection in a porous cavity from mesoscale. The influences of the value of porosity (0.4,0.7,1.0), Darcy number (10 -4, 10 -2),Rayleigh number (105~107), and inclination angle (0° ~90°) on convective heat transfer were dis-cussed. Results indicate that the isothermal lines shifted to the bottom with the inclination angle of the cavity. At Da=10 -4,the streamlines presented symmetrical distribution. As the Darcy number increased,the streamlines on the right side of the porous cavity bypassed the hot square obstacle and passed the left side, so the distribution of streamlines shifted. The average Nusselt number on hot sidewall, Nuave, presented a certain trend with increasing inclination angle. When the value of the porosity ε,Da number,and Ra number increased,the natural convection and heat transfer ability between fluid and hot wall surface was enhanced.%为了研究内置高温体倾斜多孔腔体中流体流动与传热机理,本文采用格子Boltzmann方法从介观尺度对其多孔腔体内自然对流现象进行了模拟研究,讨论了孔隙度ε(0.4,0.7,1.0)、Da数(10 -4,10 -2)、Ra数(105~107)及倾角θ(0° ~90°)等参数对其对流传热的影响.模拟结果表明:等温线会随着腔体倾斜向底部偏移;Da=10 -4时,流线呈现对称分布特性,Da数增大时,多孔方腔右侧流线会绕过高温方块经过左边区域,流线分布发生偏移.热壁面上平均Nusselt数Nuave随倾角增大呈现特定变化规律,增大孔隙度ε、Da数、Ra数时,均可以增强流体与热壁面之间的自然对流传热能力.